There are more messages hidden in the Wales family Christmas card than you probably think

If we know anything about the royals, it's that they pay attention to the details – and with the recently released family Christmas card, which shows the two of them alongside their children Prince George, Princess Charlotte and Prince Louis, they are sending a “strong message”.

The black and white photo is different from previous Christmas cards, and its casual clothing and the position of Kate, George and Charlotte all have a deeper meaning, said body language expert Judi James The sun.

In the photo, the family of five wears white shirts and dark trousers and looks relaxed as they smile at the camera. James said the “monochrome photo may not suggest a typical Christmas look” and there is “a very strong message being sent out by the Prince and Princess of Wales and their three children”: It boils down to “that they are a very cool and very unbreakable family unit,” she said. “The strong sense of a close, loving, uniformed grouping and the strong monochrome – plus the relaxed and confident body language – come across as the emotional equivalent of having a moat and a drawbridge around them.”

James added: “Here we are shown the strength and absolute confidence of the stripped-down family brand, without all the frills and trappings of their royal status. We know they look great in evening wear and royal regalia, but this is the more casual and much more tangible version, and if anything it proves that they have charisma with or without diamonds and medals. The casual jeans and white shirts look effortlessly cool on everyone, and the simple 'uniform' signals teamwork and group strength.”

Although they form a unit as a family, “their body language defines them as five individual personalities,” James said. “Each of them wears a different smile and their poses suggest a slow but seismic shift in the balance of power, just like in any other close and loving family as the children begin to grow up.”

James specifically noted Charlotte's position in the photo: “Previous Christmas cards have shown poses built around William,” she said. “Here, however, it seems like everything is built around Charlotte. She sits in the middle of the pose while the others stand, looking confident, relaxed and elegant. Even if you took the others out of the pose, she would still be a cover photo.” James particularly zoomed in on “her radiant smile with her eyes and her symmetrical smile with her lips,” which signal “authentic happiness.”

“But there is also a more subtle and poignant factor in the way the group has gathered around the daughter in a chair,” said James. “Charlotte looks so much like the late Queen and that central, status-conscious pose and beautiful smile are like echoes of Elizabeth when she was young. This effect does not seem to have been intentional but it is nevertheless quite a moving message in this family Christmas card.”

As for William, James noted his “head tilt” which “suggests a desire to be liked,” she said. “His smile and pose have the expression of a proud father who is happily beginning to be pushed to the back row as his three more independent children come to the front. He still has a hand on Prince Louis' shoulder, but his youngest son's grin suggests that as time goes on he will need less and less protection from his father.”

And don't miss Kate's romantic cues – “Kate leans into William's torso to make this pose subtly romantic too,” James said. “Her perfect Duchenne smile seems more confident than William's, and with her husband on one side and son George leaning against her torso on the other, the sense of unity and loving continuity comes across as strong.”

And what about George, our future king? “In his pose, Prince George looks more relaxed and grown-up than ever,” said James. “He is smiling, but he is not following the group norm with his bared-toothed smile. This is one of the first poses where he looks very much like his own young man with his own identity, rather than William's mini-me. George's best smile was photographed by his mother and he tended to look a little uncomfortable in formal poses. But here he has one hand casually in his pocket and his smile is reflected in his eye expression with a gentle, closed-lip smile.”

The photo was taken by photographer Josh Shinner in Windsor earlier this year and is particularly informal compared to King Charles and Queen Camilla's more formal Christmas card, also released yesterday.